From what I understand, this is mostly because of the terrible reputation Ohnar West garnered while they were bigger (and then did absolutely nothing to attempt to dispel once they weren't bigger anymore).
Environmental determinism is out of vogue in reality, but I'm a firm believer of it in BM. Ohnar West, like the multitude of realms that resembled it on EC, is cursed with terrible geography. They were always going to be at a disadvantage.
